Process of obtaining by-products from distillery-slop.



ALADAR VON LASZLOFFY, OF PEORIA, ILLINOIS.

PROCESS OF OBTAINING- BY-PRODUCTS FROM DISTILLEEY-SIOP.

Specification of Letters Patent.

Patented July 27, 1915.

No Drawing. Original application filed January 30, 1911, Serial No.605,611. Divided and this application filed August 25, 1911.

T all whom it may concern:

Be it known that I, ALADAR VON Lasz- LOFFY, citizen of the UnitedStates, residing at Peoria, in the county of Peoria and State ofIllinois, have invented certain new and useful Improvements in Processesof Ohtaining By-Products from Distillery-Slop; and I do hereby declarethat the following is a full, clear, and exact description of theinvention, which will enable others sk1lled in the "art to which itappertains to make and use the same.

This invention relates to a new and useful process for the manufactureof by-products from slops.

The object of the invention is to recover from distillery-slop aplurality of by-products such as lactic acid, succinic acid, fat, andother materials resident therein by the aid of solvents.

In my co-pending patent application, No. 605,611 filed January 30, 1911,of which this application is a divisional one, I have described a methodof separating a mixture of organic acids, fat and glycerin from d istillery-slop by-treating slop with alcohols or mixtures of alcohols withethyl-ether, chloroform, tetrachlorid of carbon or other such mixturesin Which alcohol predominates. By this treatment a mixture ofby-products of diiferent character, but all soluble in the same solvent,is obtained and this mixture is afterward separated into the individualpi oducts making up such mixture. One of the methods of separationdescribed in said application is that of treating the mixture ofby-products with such solvents as will (llS- solve lactic and succinicacids, and fat, but will have a tendency to repel glycerin.

The recovery of lactic acid, succinic acid and fat directly fromdistillery-slop or preparations of distillery-slop, by treating it withsuch solvents as dissolve said products and have a tendency to repelglycerin is the object of the present process.

By preparations of distillery-slop I mean the various forms into whichdistillery slop may be brought by filtering, evaporating, drying or byany other means.

I use in the present process, as already mentioned. a solventthatdissolves fat and the organic acids of the slop but which does not mixwith glycerin. For instance. such a solvent may be ether, chloroform,benzol, benzin, other hydrocarbons, the chlorderivates of hydrocarbonsor mixtures of them Serial No. 645,912.

stances, as I have found that all fat-solvents or their mixtures have,to a certain degree at least, the property of dissolving the organicacid present in the slop and that the differences of their action inthat respect is, therefore, only a difference of degree. I use,preferably, however, ethyl-ether which dissolves the lactic and succinicacids sufliciently rapid and still gives products of high purity at thesame time, leaving the residue in the best condition as a feed.

I have so far explained the principle of my invention and will nowdescribe the other steps of my process wherein the preparatory treatmentof the slop takes place before the various steps of extraction.

In my said co-pending patent application I have given a detaileddescription of the manner in which the slop is prepared for thesolvent-treatment. I can and do use all of the preparatory stepsdescribed therein with equal advantage in the present process. Thesesteps may be biological or chemical, or physical. The biological stepsconsist in propagating in the slop a growth of fungi for the purpose ofbinding or eliminating certain easily soluble impurities, and the fungican be afterward separated from the slop. A further and importantpurpose of the growth of fungi in the slop may be to increase theabsolute amount of by-products in the same, for instance, doing so veryeffectively by a lactic acid fermentation. By adding a small amount ofcarbohydrates to the slop and then subjecting the slop to said lacticacid fermentation a larger yield of lactic acid may be obtained with buta small increase in the cost of production. The addition of a smallamount of carbohydrates to the slop is also favorable if other fungithan l11ClZlC acid bacteria are propagated in the s op.

The chemical steps consist in adding acids to the slop in order toliberate the weaker organic acids present in the slop in the shape ofsalts. These steps may also consist in neutralizing the slop beforeconcentrating the same and acidifying it after concentration, forinstance, in order to avoid corrosion ture with the solvent before orafter drying the mixture. If the liquid part of slop is treatedseparately with the solvent I preferably incorporate .the residue ofextraction with the solid part of slop and dry the mixture.

The liquid part of the slop. may also be mixed before or afterconcentrating with absorbent, material and I preferably use suchabsorbent materials as do not reduce the value of the residue as acommercial cattlefeed. The admixture of absorbent material.

may be done in order to facilitate drying and in order, also, to makethe slop more accessible to the solvent. While'I may use biological andchemical steps in preparing the slop for the extraction I can also usephysical steps only but preferably I proceed in the following way inorder to prepare the slop for the extraction. First, I

separate the slop into a solid part and into a liquid part, then theacidity of the liquid part is increased by subjecting it to alactic'acid fermentation. This soured liquid part is afterwardconcentrated in vacuum to'the consistency of a syrup and this syrup isnow mixed with the solid part of slop and the mixture dried.

It is not necessary to absolutely drythe slop for carrying out theprocess since its great bulk may be reduced by removing the largest partof the water therefrom or reduced to the syrupy consistency described.But I prefer to dry it because the contact of the fat-solventswith theslop can be better effected when the slop is treated in a drystate and Ican use the total slop or parts of this slop which may have beenseparated from the total slop by physical or chemical means.

In the claims wherever the term slop is used instead of the slop I meaneither the total slop, or part of the slop, or any slop which hasundergone some preparatory treatment before the extraction of thebyproducts. V

The next step of my process is to bring together the properly preparedslop with the solvent. Various methods may be used fected.

for effecting this. It is found to be most convenient and preferable toplace the dried slop in an apparatus similar to that used for theextraction of fat, and the solvent is caused to pass continuouslythrough the said slop the resulting solution being continuously drawn OEand continuously concentrated, the vapor arising from the boilingsolution being condensed and passedthrough the slop, again condensed andagain passed through and repeated until the slop is exhausted of itsbyproducts. This operation can further be made a continuous one bycontinuously bringing the dried slop and the solvent together andcontinuously separat ing the solution from the residue.-

The' solvent treatment may take place at any tei .perature desired atany ordinary atmospheric pressure or even at higher or lower pressures.Higher temperature and pressure increase the speed of extraction butdecrease. the purity of the products. The solvent solution so obtainedis concentrated by evaporating the solvent completely or partiallytherefrom and the further treatment consists in separating the resultingmixture of by-products into components. The solvents are recovered fromthe final residue preferably by heating said residue, for instance, byblowing a current of steam through the same.

The solution obtained by this process contains lactic acid and succinicacid and fat if the slop contains the latter. If it contains no fat,which is an exception, then, of course,

I obtain the lactic and succinic acids and no fat. The fat is bestseparated from themixture by evaporating the solvent until said fat isliberated. Now the fat can be readily and easily separated from theother products by reason of its difierence in specific gravity from saidother products since it does not mix with the other products in the.absence of a common solvent but rises to the surface and can be drawnoff. The remaining solution containing the lactic and succinic acids maybe of course, one of the final products of the process or said solutioncan be further separatedinto its components. This separation can bebrought about either by chemical or physical means, the latter includingdistillation. The chemical or physical means, with the exception ofdistillation employed for the separation of the lactic from the succinicacid, have a common purpose that of making one of the components solublewhile the other remains insoluble whereby a separation can be readily.ef-

An easy-separation of the succinic acid from the lactic acid, althoughan incomplete one, can be obtained by allowing the concentrated mixtureof lactic and succinic acid to stand until the latter crystallizes.crystals can then be readily separated from The the remaining liquid.Or, again, the mixture containing the lactic and succinic acids can beseparated by first neutralizing the acids and then separating the saltsfrom each other by treating the mixture with solvents which dissolve thesalts of one acid but not those of the other. The acids are laterliberated from their salts with stronger acids. The lactic and succinicacids can also be separated from each other by distillation since thelactic acid has a much lower boiling point than the succinic acid andwill pass off leaving the latter. But believing that I am the first torecover lactic and succinic acids from distillery-slop by treating theslop with a fat-solvent I do not confine myself to any one of thespecial methods enumerated for the separation of these substances fromthe solution obtained by the fat-solvent treatment. 7

Thus far I have not stated that the solvent is recovered from thesolution but it is to be stated that wherever either in thespecification or claims the recovery of a solvent is not expresslymentioned, it is understood that this recovery takes place, foreconomical reasons particularly, and I can use for their recovery anystyle of distilling or rectifying apparatus.

The following is an example of the manner in which my process is carriedout in practice':30,000 gallons of slop which represents the amountderived from the fermentation of 1000 bushels of grain are, preferablydirectly after leaving the distilling apparatus, separated by the aid offilter-presses, for example into two parts, a solid and a liquid. Theliquid part is placed in a tub and to it is added 500 gallons of aculture of lactic acid bacteria prepared for instance, by adding apure-culture of lactic acid bacteria to a wort, obtained by filtering acorn-mash made in the usual way from 20 bushels of corn and 2 bushels ofmalt. This addition of 500 gallons culture of lactic acid bacteriastarts the lactic acid fermentation in the liquid and also imparts to itas a natural consequence a small amount of carbohydrates. Instead ofadding a culture in this shape the culture of lactic bacteria may alsobe represented by 500 gallons of thin slop which has been inoculatedwith said lactic bacteria. The lactic acid fermentation in the bulk ofthe liquid slop can be also a spontaneous one that is to say it maystart therein by the presence of bacteria in the unclean vessel in whichthe slop is placed or from the air or even by other similar ways. But itis to be preferred, as

in all biological processes, to start the fermentation with a pure seedof lactic bacteria and this addition to the liquid part of the sloptakes place when the latter is cooled to about 125 Fahrenheit, thistemperature being maintained in order to insure the production of a pureacid. After 24 to 48 hours of fermentation the soured thin slop isconcentrated in a n1ultiple-effect vacuum-evaporator to the consistencyof a syrup and this is now mixed with filtercakes obtained from theslop. In practice, where the distillery operations are carried on daily,the filter-cakes, which answer the same as the solid part of the slop,are mixed with the syrup filtered one or two days prior during whichtime the liquid part has been soured and concentrated. This method ofsouring admits of localizing the biological process to the substancesdissolved in the slop, the acid being obtained without the action of thebacteria on the real proteinsubstances which being insoluble remain inthe cake or solid part of the slop. The cakes are thoroughly mixed withthe sour syrup and the mixture dried on any suitable drying apparatus,for instance, a rotary drier and it is preferable to do the drying at alow temperature. The cake can also be dried if desired before mixing itwith the syrup and the mixture may be again dried. The product resultingfrom drying this mixture differs from ordinary dried slop inasmuch as itcontains a large amount of lactic acid. This dried slop is now groundand placed in an apparatus of similar construction to that used for theextraction of fat. The essential parts of such an apparatus which,however, form no part of my invention, are a vessel with a perforatedfalse bottom in which the dried slop is placed, a still in which thesolvent solution is to be boiled, and a reflux cooler to condense thevapor coming from this still and return it to the dried slop throughwhich it percolates. The still is provided with a steamcoil which keepsthe solution boiling, the said apparatus also including the necessaryreceivlng tanks for the solvent and for the resulting solutions.

In the still is placed ethyl-ether to the amount of substantially twicethe volume of that of the dried slop placed in the percolating, vessel.Theether is caused to boil and its vapor ascends to the reflux-cooler,percolates through the dried slop and returns to the still. Thisoperation is kept on continuously until the slop is practicallyexhausted of organic acids, which can be easily determined by testingthe acidity of a small amount of the ether by the usual chemical meansas it comes from the percolating vessel. When the proper stage isreached the operation is interrupted and the solution contained in thestill is withdrawn preferably after evaporating the solvent from thesolution. It contains fat, lactic and succinic acidsin a state of highpurity and the treatment of 'said solution will be explained later.

By evaporating the solvent the fat is liberated and arises, aftersometime, to the top and forms a separate layer which 1s.'

drawn ofi separately and the resulting mixture of lactic and succinicacids may be one of the final products of this process, or may befurther separated into components, as already stated, but if boiled downfar enough and allowed to stand at low temperature the largest part ofthe succinic acid crystallizes and can be readily separated from theremaining solution. The mixture of lactic and succinic-acids may also beneutralized for instance with lime or carbonate of lime and theneutralized mixture treated with solvents, for instance with water. Thewater dissolves the lactates much easier than the succinates and in thiswav a separation can be effected, and the acids can be afterwardliberated from their salts bystronger acids.

In certain of the claims I shall use the terms removing water from theslop and drying slop. In explanation of the use of these terms I wish tosay that in the meaning of the first the bulk of the water may beremoved without absolutely drying the material, whereas in the use ofthe second term the treatment may go as far as drying the materialcompletely. As already intimated herein treatment with the extractingagents may be done in either condition although the extraction from drymaterial is more readily accomplished.

Having described my invention, I claim 1- 1. In the process ofrecovering a plurality of by-products from distillery-slop with the aidof solvents, the process which consists in removing water from slop,treating said slop with a fat-solvent capable of dissolving lactic acidand succinic acid and which has a tendency to repel glycerin andseparating the solution resulting from this treatment from the insolublepart.

2. In the process of recovering a plurality of by-productsfromdistillery-slop with the aid of solvents the process which consistsin drying slop, treating the dried slop with a fat-solvent capable ofdissolving lactic acid and succinic acid and which has a tendency torepel glycerin, and separating the solution resulting from thistreatment from the insoluble part.

The process of recovering lactic acid, and succinic acid from a mixtureof substances derived from distillery slop consisting in treating saidmixture wtih a fatsolvent capable of dissolving the named acids andhaving a tendency to repel glycerin, and separating the'solutionresulting from this treatment from the insoluble part.

-l. In the process of recovering a plurality of by-products fromdistillery-slop, the process which consists in acidifying slop, removingwater from slop, treating said slop with a fat-solvent capable ofdissolving lactic and tendency to repel the solution resulting from thistreatment from the insoluble part.

5. The process of recovering from distillery-slop a solution'co'ntainingfat, lactic and succinic acids, and a dryresidue, consisting inseparating slop into a solid part and a liquid part, removing water fromthe liquid part, treating the liquid part with a tat-solvent capable ofdissolving lactic and succinic acids and which has a tendency to repelglycerin, and separating the solution resulting from this treatment fromthe insoluble part.

6. In the process of recovering a plurality of by-products fromdistillery-slop, the process which consists in first separating amixture of substances derived from distillery-slop into a solution ofby-products and into a residueby treating the same with a fat-solventcapable of dissolving lactic and succinic acids and which has a tendencyto repel glycerin, recovering the solvent from said solution therebyliberating the fat, and

separating the fat from the remaining mlxture of by-pro'ducts.

7. In the process of recovering lactic and succinic acids, and fat fromdistillery-slop, the process which consists in first separating amixture of substances derived from distillery-slop into a solution ofby-products and into a residue by treating the same with a fat-solventcapable of dissolving lactic and succinic acids and which has a tendencyto repel glycerin, and afterward separating from said solution a part ofthe by-products by crystallization. t

8. In the process of recovering lactic and succinic acids, and fat fromdistillery-slop,

the process which consists in first separating a nnxture of substancesderived from dissuccinic acids and which has a V glycerln, andseparating v tillery-slop into a solution of by-products and into aresidue by treating the same with a fat-solvent capable of dissolvinglactic and succinic acids and which has a tendency to repel glycerin,recovering the solvent from the solution and afterward separating fromthe resulting mixture a part of the byproducts by crystallization.

In testimony whereof I allix my signature, in presence of two witnesses.

Amman VON LASZLOFEY. lVitnesses: I

iEnxicn M. Bennett, 7L. M. TIIURLO\V.

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